A performance of Beethoven’s Ninth Symphony is always a great occasion. But here, crowning a complete Proms Beethoven symphony cycle from the West-Eastern Divan Orchestra and its artistic director Daniel Barenboim, the atmosphere seemed especially charged.

It’s been a gruelling week for the performers, especially for Barenboim, who’s led all the symphonies from memory, and conducted several works by another composer of radical daring, Pierre Boulez. We caught a glimpse of Barenboim’s weariness, in the unusually long pauses he took between movements. But the moment the music began, he shrugged it off and became his usual galvanically energised self.

This performance of the Ninth had both the grandeur and the little weaknesses we’ve heard in the cycle as a whole, writ large.

Barenboim wants to project these symphonies into a lofty timeless realm, so ''period performance’’ lightness isn’t on his agenda. For the same reason, he didn’t deign to adjust his vision to the hall’s difficult acoustics. This was a problem at the hushed, trembling opening, which was so hushed that we couldn’t hear the strings’ urgent pulsing beneath the opening phrase (this has been a problem throughout the series, especially in the quieter moments of Boulez’s music).

There were other symptoms of Barenboim’s disdain for detail, and the somewhat approximate quality in his beat. The beginning of the Scherzo was disappointingly mushy, and only found its form several bars in. And the fanfare which begins the Finale was feeble, as if Barenboim had muted its shocking dissonance.

But by the end the performers had risen to the music’s aspiring intensity. The Trio of the Scherzo could have seemed ponderous at Barenboim’s unusually slow tempo; instead it was movingly spacious, in a way that carried us back to the Pastoral Symphony heard several nights previously.

In the Finale, it helped that the choir was the National Youth Choir; it needed young lungs and throats to hold the cruelly taxing, blazing major chord on ''Gott’’ as long as Barenboim wanted. The soloists, particularly bass René Pape, were full of fire and conviction. The ending was as blazing as it should be, but the most eloquent moment came in the recitative from the massed double-basses at the beginning of the Finale. The sense that they were struggling to utter some great thought has rarely been more movingly expressed.

Hear this concert on the BBC iPlayer and all the Proms live on Radio 3 bbc.co.uk/radio3